Silk dressing gown the key to the Claremont arrest

A WOMAN'S silk dressing gown stolen off a washing line 28 years ago is believed to have been the vital clue that helped lead police to finally make an arrest in the Claremont serial killer case.

It can be revealed that in 1988 - eight years before Sarah Spiers was abducted off a Claremont street - the white kimono was dropped by an intruder who broke into the home of an 18-year-old Huntingdale woman and tried to rape her.

Her screams caused him to flee and police believe the stolen kimono was accidentally dropped by the man as he ran out of the home.

The case was never solved and the robe was put into storage at WA Police's evidence receival centre, where it sat unnoticed alongside hundreds of thousands of exhibits until just a few months ago.

As part of a continuing operation to retest old evidence with new technology, officers from the State Crime Operations team did DNA tests on the kimono.

Cold-case detectives spent Thursday night questioning a Bradley Robert Edwards in relation to the 20-year-old Claremont serial killer investigation.Justin Benson-Cooper - The West Australian

Police claim the DNA samples came back as a match to samples already on the police database - samples that had been recovered from the body of the third Claremont victim, Ciara Glennon, and from a 17-year-old woman who was grabbed in a Claremont street in 1995 and then assaulted at the nearby Karrakatta cemetery.

It told police that the serial killer they were hunting may have been the same person who dropped the kimono. While the DNA link did not give them a name for that person, it did provide detectives with fresh investigative opportunities contained within the pages of the 1988 case file.

As a result of re-examining that case, it's understood the major breakthrough - the details of which are not yet clear - came within weeks.

That breakthrough culminated in the dramatic arrest on Thursday of 48-year-old Telstra worker Bradley Robert Edwards at his home in Acton Avenue in Kewdale.

It is understood a DNA sample was taken from him immediately after his arrest and the positive results came back about 12 hours later, leading to him being formally charged.

The junior athletics coach appeared in court yesterday charged with the wilful murder of two of the Claremont victims, Jane Rimmer, 23, and Ms Glennon, 27.

Police Commissioner Karl O'Callaghan said yesterday inquiries into the death of Ms Spiers, whose body has never been found, were continuing.

Mr Edwards was also charged over the Huntingdale attack in 1988 and with the abduction and rape of the 17-year-old woman at Karrakatta cemetery.

He has not been charged in relation to the disappearance of Sarah Spiers.

Speaking at police headquarters, surrounded by his command team, Mr O'Callaghan said the result was a credit to the hard work and commitment of hundreds of officers over two decades.

"This has already been the biggest and most complex investigation in WA Police history," Mr O'Callaghan said.

"Hundreds of police officers have worked on this case over the 20 years. The commitment of the WA police and its officers has never wavered.

"We never give up."

Families of the three murder victims had been kept closely informed of the developments as they unfolded this week.

None was willing to be interviewed yesterday.

However, Sarah Spiers' father Don, who is holidaying in Bali, posted a message on Facebook to inform friends that his family were aware of the developments.

"Hello to all my Facebook friends and others," Mr Spiers said. "I'm just calling to let you know Carol and I are OK - we're overseas at the moment with Amanda and the girls.

"We're quite comfortable. We were pre-warned with what was going to happen. The task force is staying in touch with us and keeping us up to date on what is happening."

Mr O'Callaghan acknowledged the continuing suffering of the families and thanked them for their support over two decades.

"I want to pay tribute to the Spiers, Rimmer and Glennon families and the victim of the 1995 attack for their patience, understanding and support during the investigation," he said.

"These crimes shocked the West Australian public and police understand the high level of community and media interest.

Sarah Spiers, Jane Rimmer and Ciara Glennon all disappeared from Claremont, however Edwards has not been charged in relation to Ms Spiers’ disappearance. Supplied

"But now that a person has been charged, I want to take this opportunity to reiterate the need to respect the judicial process.

"It is timely to remind everybody that comments posted on social media are also not immune from contempt proceedings."

Mr Edwards' Kewdale home remained a major crime scene yesterday as forensic police continued to scour the property for clues.

Several items belonging to Ms Rimmer and Ms Glennon were never recovered with their bodies and it is understood police are searching for those items.

Mr O'Callaghan indicated yesterday that there were other matters police were investigating, but he would not give details.

"If anyone believes they have any information that could assist our ongoing investigation, please call Crime Stoppers," he said.